1. Field of the Invention
This invention relates generally to air purification systems and more particularly to systems for reducing particles in air.
2. Description of the Prior Art
When a fuel burns incompletely, pollutants such as particles and hydrocarbons are released into the atmosphere. The United States Environmental Protection Agency has passed regulations that limit the amount of pollutants that, for example, diesel trucks, power plants, engines, automobiles, and off-road vehicles can release into the atmosphere.
Currently, industries attempt to follow these regulations by adding scrubbers, catalytic converters and particle traps to their exhaust systems. However, these solutions increase the amount of back pressure exerted on the engine or combustion system, decreasing performance. In addition, the scrubbers and particle traps themselves become clogged and require periodic cleaning to minimize back pressure.
Radiation sources and heaters have been used in exhaust systems, for example, to periodically clean the particle traps or filter beds. Others solutions have included injecting fuel into the filter beds or exhaust streams as the exhaust enters the filter beds to combust the particles therein. However, the filter beds can be sensitive to high temperatures and the radiation sources and heaters must be turned off periodically.
Air purification systems currently use one of two methods to remove particles such as dust, biological toxins, and the like from the air in a room. One type of system uses an ionizer to provide a surface charge to the air-borne particles so that they adhere to a surface. However, ionizers emit ozone, a respiratory irritant, into the air. Another type of system uses a filter, such as a HEPA filter, to trap particles as the air flows through the filter. However, filters need to be replaced or cleaned periodically. Both methods require a fan to circulate the air, which requires electricity and can be loud.